There has been proposed an image forming apparatus that is capable of executing a direct print. The image forming apparatus has a mounting portion, an operation unit and an image forming unit. The mounting portion mounts an external memory that stores data. The operation unit is used to input a command for starting of printing of an image based on the data, a selection of the data as a printing object, etc. from a user. The image forming unit acquires the data from the external memory mounted to the mounting portion based on an operation of the operation unit, and converts the acquired data into printing data that is printable by the image forming unit in order to print the image.
Further, in the image forming apparatus of this kind, the printing data generated at a starting time of printing may be stored on a memory device such as a hard disk drive (HDD), etc. When a repeat button is operated, the printing data stored on the HDD is reprinted based on information at a generating time of the printing data. When such reprinting is performed, it is not necessary to acquire the data from the external memory again and convert the acquired data into the printing data. Therefore, reprinting can be efficiently executed.
However, the printing data is still left in the HDD after printing. Thus, such reprinting is not preferable in terms of security of the printing data.
Therefore, in order to maintain security, JP-A-2003-333226 discloses a configuration in which erasing the stored printing data on the HDD is performed when a predetermined data holding time has passed after the printing data is stored on the HDD.
However, in the related image forming apparatus disclosed in JP-A-2003-333226, as the data holding time is lengthened, the possibility that the printing data stored on the HDD can be utilized in reprinting is increased. Accordingly, it is possible to improve usability at an executing time of the reprinting. However, the possibility that the printing data is reprinted by another user is also increased. Therefore, it is difficult to maintain the security of the printing data.
Further, in the related image forming apparatus, as the data holding time is shortened, the possibility that the printing data stored on the HDD can be utilized in reprinting is reduced. Therefore, although the security of the printing data may be maintained, it is difficult to maintain the usability when a user executes the reprinting.
That is, in the related image forming apparatus for erasing the printing data stored on the HDD after the passage of the data holding time, it is difficult to balance usability at the executing time of the reprinting and the security of the printing data.